Is there a C library function to open a file found in a path?
in [Unix Programming]
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From: Mark Hobley on 28 Feb 2010 21:08 I am using Linux. Is there a C library function to search along a path to locate a file? Supposing I have an environment variable FOOPATH as follows: BARPATH=/var/test/dir1:/var/test/dir2:/dirdoesnotexist:/home/fooser I want to open the file foo.txt, which may be located in one of the directories in BARPATH. Is there a library function that will provide that facility, or do I need to create a buffer, and start slicing and splicing the pathname and filename from within my program? This is a core program, so /usr/lib may not yet be mounted when the search takes place, so ideally a function from a library normally found in the /lib directory is preferred. Also, some directories within BARPATH may not yet exist. Will the library function skip over the non-existent ones? Mark. -- Mark Hobley Linux User: #370818 http://markhobley.yi.org/
From: Ramon F Herrera on 28 Feb 2010 22:24 On Feb 28, 8:08 pm, markhob...(a)hotpop.donottypethisbit.com (Mark Hobley) wrote: > I am using Linux. > > Is there a C library function to search along a path to locate a file? > > Supposing I have an environment variable FOOPATH as follows: > > BARPATH=/var/test/dir1:/var/test/dir2:/dirdoesnotexist:/home/fooser > > I want to open the file foo.txt, which may be located in one of the > directories in BARPATH. > > Is there a library function that will provide that facility, or do I need > to create a buffer, and start slicing and splicing the pathname and filename > from within my program? > > This is a core program, so /usr/lib may not yet be mounted when the search > takes place, so ideally a function from a library normally found in the /lib > directory is preferred. > > Also, some directories within BARPATH may not yet exist. Will the library > function skip over the non-existent ones? > > Mark. > > -- > Mark Hobley > Linux User: #370818 http://markhobley.yi.org/ An educated guess is that what you want is too specialized. The most you could find is a path splitter. -Ramon
From: Barry Margolin on 28 Feb 2010 22:34 In article <9491c2b9-a6ca-47fa-93ad-9055920796ce(a)f8g2000yqn.googlegroups.com>, Ramon F Herrera <ramon(a)conexus.net> wrote: > On Feb 28, 8:08�pm, markhob...(a)hotpop.donottypethisbit.com (Mark > Hobley) wrote: > > I am using Linux. > > > > Is there a C library function to search along a path to locate a file? > > > > Supposing I have an environment variable FOOPATH as follows: > > > > BARPATH=/var/test/dir1:/var/test/dir2:/dirdoesnotexist:/home/fooser > > > > I want to open the file foo.txt, which may be located in one of the > > directories in BARPATH. > > > > Is there a library function that will provide that facility, or do I need > > to create a buffer, and start slicing and splicing the pathname and filename > > from within my program? > > > > This is a core program, so /usr/lib may not yet be mounted when the search > > takes place, so ideally a function from a library normally found in the /lib > > directory is preferred. > > > > Also, some directories within BARPATH may not yet exist. Will the library > > function skip over the non-existent ones? > > > > Mark. > > > > -- > > Mark Hobley > > Linux User: #370818 �http://markhobley.yi.org/ > > An educated guess is that what you want is too specialized. The most > you could find is a path splitter. It's actually a pretty common operation (MANPATH, LD_LIBRARY_PATH, PATH). But AFAIK there's no standard library function to do it. Perhaps the problem is that each of them has restrictions on the types of files they're looking for; for instance, when searching MANPATH, it actually has to go into subdirectories, and append a suffix dependent on the subdirectory. PATH only cares about executables, and LD_LIBRARY_PATH allows for a variety of suffixes because of version numbers. -- Barry Margolin, barmar(a)alum.mit.edu Arlington, MA *** PLEASE post questions in newsgroups, not directly to me *** *** PLEASE don't copy me on replies, I'll read them in the group ***
From: Ramon F Herrera on 28 Feb 2010 22:38 On Feb 28, 9:34 pm, Barry Margolin <bar...(a)alum.mit.edu> wrote: > In article > <9491c2b9-a6ca-47fa-93ad-905592079...(a)f8g2000yqn.googlegroups.com>, > Ramon F Herrera <ra...(a)conexus.net> wrote: > > > > > On Feb 28, 8:08 pm, markhob...(a)hotpop.donottypethisbit.com (Mark > > Hobley) wrote: > > > I am using Linux. > > > > Is there a C library function to search along a path to locate a file? > > > > Supposing I have an environment variable FOOPATH as follows: > > > > BARPATH=/var/test/dir1:/var/test/dir2:/dirdoesnotexist:/home/fooser > > > > I want to open the file foo.txt, which may be located in one of the > > > directories in BARPATH. > > > > Is there a library function that will provide that facility, or do I need > > > to create a buffer, and start slicing and splicing the pathname and filename > > > from within my program? > > > > This is a core program, so /usr/lib may not yet be mounted when the search > > > takes place, so ideally a function from a library normally found in the /lib > > > directory is preferred. > > > > Also, some directories within BARPATH may not yet exist. Will the library > > > function skip over the non-existent ones? > > > > Mark. > > > > -- > > > Mark Hobley > > > Linux User: #370818http://markhobley.yi.org/ > > > An educated guess is that what you want is too specialized. The most > > you could find is a path splitter. > > It's actually a pretty common operation (MANPATH, LD_LIBRARY_PATH, > PATH). But AFAIK there's no standard library function to do it. > Perhaps the problem is that each of them has restrictions on the types > of files they're looking for; for instance, when searching MANPATH, it > actually has to go into subdirectories, and append a suffix dependent on > the subdirectory. PATH only cares about executables, and > LD_LIBRARY_PATH allows for a variety of suffixes because of version > numbers. > I was about to suggest the OP to take a look at the program "which.exe", Barry. -Ramon
From: Mark Hobley on 1 Mar 2010 03:08 In comp.unix.programmer Ramon F Herrera <ramon(a)conexus.net> wrote: > An educated guess is that what you want is too specialized. The most > you could find is a path splitter. I am shocked that there is no path walker. A path splitter would be of some help, if there is one. > I was about to suggest the OP to take a look at the program > "which.exe", Barry. On my system which is a shell script. I wonder if there is a C implementation of it though ... I looked at the man pager, but the path walker bit was written in perl, and has the added complication of using an indexed database, rather than a direct path walk. (even the heirloom version did this). Mark. -- Mark Hobley Linux User: #370818 http://markhobley.yi.org/
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