Is it normal that LD_LIBRARY_PATH variable is missing from an environment?

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I have found by coincidence that on my Debian Jessie there is no LD_LIBRARY_PATH variable (to be exact printenv | grep LD shows nothing related to linker and echo "$LD_LIBRARY_PATH" shows also nothing).



This is the case in x terminal emulator (which might clear it due to setgid) as well as in basic terminal (Ctrl+Alt+F1).



I know that LD_LIBRARY_PATH may be considered bad so Debian may block it somehow, but on the other hand there are a few files in /etc/ld.so.conf.d/ that contains some directories to be added to LD_LIBRARY_PATH. None of my rc files (that I know of) mess with LD_LIBRARY_PATH either.



Why I don't see an LD_LIBRARY_PATH variable?










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    up vote
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    down vote

    favorite
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    I have found by coincidence that on my Debian Jessie there is no LD_LIBRARY_PATH variable (to be exact printenv | grep LD shows nothing related to linker and echo "$LD_LIBRARY_PATH" shows also nothing).



    This is the case in x terminal emulator (which might clear it due to setgid) as well as in basic terminal (Ctrl+Alt+F1).



    I know that LD_LIBRARY_PATH may be considered bad so Debian may block it somehow, but on the other hand there are a few files in /etc/ld.so.conf.d/ that contains some directories to be added to LD_LIBRARY_PATH. None of my rc files (that I know of) mess with LD_LIBRARY_PATH either.



    Why I don't see an LD_LIBRARY_PATH variable?










    share|improve this question

























      up vote
      14
      down vote

      favorite
      3









      up vote
      14
      down vote

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      3





      I have found by coincidence that on my Debian Jessie there is no LD_LIBRARY_PATH variable (to be exact printenv | grep LD shows nothing related to linker and echo "$LD_LIBRARY_PATH" shows also nothing).



      This is the case in x terminal emulator (which might clear it due to setgid) as well as in basic terminal (Ctrl+Alt+F1).



      I know that LD_LIBRARY_PATH may be considered bad so Debian may block it somehow, but on the other hand there are a few files in /etc/ld.so.conf.d/ that contains some directories to be added to LD_LIBRARY_PATH. None of my rc files (that I know of) mess with LD_LIBRARY_PATH either.



      Why I don't see an LD_LIBRARY_PATH variable?










      share|improve this question















      I have found by coincidence that on my Debian Jessie there is no LD_LIBRARY_PATH variable (to be exact printenv | grep LD shows nothing related to linker and echo "$LD_LIBRARY_PATH" shows also nothing).



      This is the case in x terminal emulator (which might clear it due to setgid) as well as in basic terminal (Ctrl+Alt+F1).



      I know that LD_LIBRARY_PATH may be considered bad so Debian may block it somehow, but on the other hand there are a few files in /etc/ld.so.conf.d/ that contains some directories to be added to LD_LIBRARY_PATH. None of my rc files (that I know of) mess with LD_LIBRARY_PATH either.



      Why I don't see an LD_LIBRARY_PATH variable?







      linux environment-variables ld






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      share|improve this question













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      share|improve this question








      edited Sep 26 '17 at 11:21









      Kusalananda

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      106k14209327










      asked Sep 26 '17 at 11:04









      calavera.info

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      291112




















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          Yes, it is normal that you don't have any explicit LD_LIBRARY_PATH. Read also ldconfig(8) and ld-linux(8) and about the rpath. Notice that ldconfig updates /etc/ld.so.cache, not the LD_LIBRARY_PATH. Sometimes you'll set the rpath of an executable explicitly with -Wl,-rpath,directory passed to gcc at link time.



          If you need a LD_LIBRARY_PATH (but you probably should not), set it yourself (e.g. in ~/.bashrc).



          If you need system wide settings, you could e.g. consider adding /usr/local/lib/ in /etc/ld.so.conf and run ldconfig after installation of every library there.



          AFAIK $LD_LIBRARY_PATH is used only by the dynamic linker ld-linux.so (and by dlopen(3) which uses it) after execve(2). See also ldd(1).



          Read Drepper's How To Write Shared Libraries for more.






          share|improve this answer






















          • That was my mistake, I though that LD_LIBRARY_PATH is the product of running ldconfig. Meanwhile it is the input of ldconfig alongside with files in /etc/ld.so.conf.
            – calavera.info
            Sep 26 '17 at 11:13






          • 1




            My feeling is that ldconfig don't use $LD_LIBRARY_PATH (which is only used at ld-linux.so time)
            – Basile Starynkevitch
            Sep 26 '17 at 11:15







          • 3




            @calavera.info it's neither. The dynamic linker uses LD_LIBRARY_PATH together with the output of ldconfig at runtime. ldconfig neither uses nor changes LD_LIBRARY_PATH.
            – hobbs
            Sep 26 '17 at 19:37










          • Now I can see that I had it totally messed up, probably by spending too much time in Java, where "classpath" is virtualy the only configuration of dynamic linking. Everything seems to be clear now, thanks a lot.
            – calavera.info
            Sep 27 '17 at 8:41










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          1 Answer
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          up vote
          22
          down vote



          accepted










          Yes, it is normal that you don't have any explicit LD_LIBRARY_PATH. Read also ldconfig(8) and ld-linux(8) and about the rpath. Notice that ldconfig updates /etc/ld.so.cache, not the LD_LIBRARY_PATH. Sometimes you'll set the rpath of an executable explicitly with -Wl,-rpath,directory passed to gcc at link time.



          If you need a LD_LIBRARY_PATH (but you probably should not), set it yourself (e.g. in ~/.bashrc).



          If you need system wide settings, you could e.g. consider adding /usr/local/lib/ in /etc/ld.so.conf and run ldconfig after installation of every library there.



          AFAIK $LD_LIBRARY_PATH is used only by the dynamic linker ld-linux.so (and by dlopen(3) which uses it) after execve(2). See also ldd(1).



          Read Drepper's How To Write Shared Libraries for more.






          share|improve this answer






















          • That was my mistake, I though that LD_LIBRARY_PATH is the product of running ldconfig. Meanwhile it is the input of ldconfig alongside with files in /etc/ld.so.conf.
            – calavera.info
            Sep 26 '17 at 11:13






          • 1




            My feeling is that ldconfig don't use $LD_LIBRARY_PATH (which is only used at ld-linux.so time)
            – Basile Starynkevitch
            Sep 26 '17 at 11:15







          • 3




            @calavera.info it's neither. The dynamic linker uses LD_LIBRARY_PATH together with the output of ldconfig at runtime. ldconfig neither uses nor changes LD_LIBRARY_PATH.
            – hobbs
            Sep 26 '17 at 19:37










          • Now I can see that I had it totally messed up, probably by spending too much time in Java, where "classpath" is virtualy the only configuration of dynamic linking. Everything seems to be clear now, thanks a lot.
            – calavera.info
            Sep 27 '17 at 8:41














          up vote
          22
          down vote



          accepted










          Yes, it is normal that you don't have any explicit LD_LIBRARY_PATH. Read also ldconfig(8) and ld-linux(8) and about the rpath. Notice that ldconfig updates /etc/ld.so.cache, not the LD_LIBRARY_PATH. Sometimes you'll set the rpath of an executable explicitly with -Wl,-rpath,directory passed to gcc at link time.



          If you need a LD_LIBRARY_PATH (but you probably should not), set it yourself (e.g. in ~/.bashrc).



          If you need system wide settings, you could e.g. consider adding /usr/local/lib/ in /etc/ld.so.conf and run ldconfig after installation of every library there.



          AFAIK $LD_LIBRARY_PATH is used only by the dynamic linker ld-linux.so (and by dlopen(3) which uses it) after execve(2). See also ldd(1).



          Read Drepper's How To Write Shared Libraries for more.






          share|improve this answer






















          • That was my mistake, I though that LD_LIBRARY_PATH is the product of running ldconfig. Meanwhile it is the input of ldconfig alongside with files in /etc/ld.so.conf.
            – calavera.info
            Sep 26 '17 at 11:13






          • 1




            My feeling is that ldconfig don't use $LD_LIBRARY_PATH (which is only used at ld-linux.so time)
            – Basile Starynkevitch
            Sep 26 '17 at 11:15







          • 3




            @calavera.info it's neither. The dynamic linker uses LD_LIBRARY_PATH together with the output of ldconfig at runtime. ldconfig neither uses nor changes LD_LIBRARY_PATH.
            – hobbs
            Sep 26 '17 at 19:37










          • Now I can see that I had it totally messed up, probably by spending too much time in Java, where "classpath" is virtualy the only configuration of dynamic linking. Everything seems to be clear now, thanks a lot.
            – calavera.info
            Sep 27 '17 at 8:41












          up vote
          22
          down vote



          accepted







          up vote
          22
          down vote



          accepted






          Yes, it is normal that you don't have any explicit LD_LIBRARY_PATH. Read also ldconfig(8) and ld-linux(8) and about the rpath. Notice that ldconfig updates /etc/ld.so.cache, not the LD_LIBRARY_PATH. Sometimes you'll set the rpath of an executable explicitly with -Wl,-rpath,directory passed to gcc at link time.



          If you need a LD_LIBRARY_PATH (but you probably should not), set it yourself (e.g. in ~/.bashrc).



          If you need system wide settings, you could e.g. consider adding /usr/local/lib/ in /etc/ld.so.conf and run ldconfig after installation of every library there.



          AFAIK $LD_LIBRARY_PATH is used only by the dynamic linker ld-linux.so (and by dlopen(3) which uses it) after execve(2). See also ldd(1).



          Read Drepper's How To Write Shared Libraries for more.






          share|improve this answer














          Yes, it is normal that you don't have any explicit LD_LIBRARY_PATH. Read also ldconfig(8) and ld-linux(8) and about the rpath. Notice that ldconfig updates /etc/ld.so.cache, not the LD_LIBRARY_PATH. Sometimes you'll set the rpath of an executable explicitly with -Wl,-rpath,directory passed to gcc at link time.



          If you need a LD_LIBRARY_PATH (but you probably should not), set it yourself (e.g. in ~/.bashrc).



          If you need system wide settings, you could e.g. consider adding /usr/local/lib/ in /etc/ld.so.conf and run ldconfig after installation of every library there.



          AFAIK $LD_LIBRARY_PATH is used only by the dynamic linker ld-linux.so (and by dlopen(3) which uses it) after execve(2). See also ldd(1).



          Read Drepper's How To Write Shared Libraries for more.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Sep 26 '17 at 11:19

























          answered Sep 26 '17 at 11:06









          Basile Starynkevitch

          7,9231940




          7,9231940











          • That was my mistake, I though that LD_LIBRARY_PATH is the product of running ldconfig. Meanwhile it is the input of ldconfig alongside with files in /etc/ld.so.conf.
            – calavera.info
            Sep 26 '17 at 11:13






          • 1




            My feeling is that ldconfig don't use $LD_LIBRARY_PATH (which is only used at ld-linux.so time)
            – Basile Starynkevitch
            Sep 26 '17 at 11:15







          • 3




            @calavera.info it's neither. The dynamic linker uses LD_LIBRARY_PATH together with the output of ldconfig at runtime. ldconfig neither uses nor changes LD_LIBRARY_PATH.
            – hobbs
            Sep 26 '17 at 19:37










          • Now I can see that I had it totally messed up, probably by spending too much time in Java, where "classpath" is virtualy the only configuration of dynamic linking. Everything seems to be clear now, thanks a lot.
            – calavera.info
            Sep 27 '17 at 8:41
















          • That was my mistake, I though that LD_LIBRARY_PATH is the product of running ldconfig. Meanwhile it is the input of ldconfig alongside with files in /etc/ld.so.conf.
            – calavera.info
            Sep 26 '17 at 11:13






          • 1




            My feeling is that ldconfig don't use $LD_LIBRARY_PATH (which is only used at ld-linux.so time)
            – Basile Starynkevitch
            Sep 26 '17 at 11:15







          • 3




            @calavera.info it's neither. The dynamic linker uses LD_LIBRARY_PATH together with the output of ldconfig at runtime. ldconfig neither uses nor changes LD_LIBRARY_PATH.
            – hobbs
            Sep 26 '17 at 19:37










          • Now I can see that I had it totally messed up, probably by spending too much time in Java, where "classpath" is virtualy the only configuration of dynamic linking. Everything seems to be clear now, thanks a lot.
            – calavera.info
            Sep 27 '17 at 8:41















          That was my mistake, I though that LD_LIBRARY_PATH is the product of running ldconfig. Meanwhile it is the input of ldconfig alongside with files in /etc/ld.so.conf.
          – calavera.info
          Sep 26 '17 at 11:13




          That was my mistake, I though that LD_LIBRARY_PATH is the product of running ldconfig. Meanwhile it is the input of ldconfig alongside with files in /etc/ld.so.conf.
          – calavera.info
          Sep 26 '17 at 11:13




          1




          1




          My feeling is that ldconfig don't use $LD_LIBRARY_PATH (which is only used at ld-linux.so time)
          – Basile Starynkevitch
          Sep 26 '17 at 11:15





          My feeling is that ldconfig don't use $LD_LIBRARY_PATH (which is only used at ld-linux.so time)
          – Basile Starynkevitch
          Sep 26 '17 at 11:15





          3




          3




          @calavera.info it's neither. The dynamic linker uses LD_LIBRARY_PATH together with the output of ldconfig at runtime. ldconfig neither uses nor changes LD_LIBRARY_PATH.
          – hobbs
          Sep 26 '17 at 19:37




          @calavera.info it's neither. The dynamic linker uses LD_LIBRARY_PATH together with the output of ldconfig at runtime. ldconfig neither uses nor changes LD_LIBRARY_PATH.
          – hobbs
          Sep 26 '17 at 19:37












          Now I can see that I had it totally messed up, probably by spending too much time in Java, where "classpath" is virtualy the only configuration of dynamic linking. Everything seems to be clear now, thanks a lot.
          – calavera.info
          Sep 27 '17 at 8:41




          Now I can see that I had it totally messed up, probably by spending too much time in Java, where "classpath" is virtualy the only configuration of dynamic linking. Everything seems to be clear now, thanks a lot.
          – calavera.info
          Sep 27 '17 at 8:41

















           

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