Mercurial > hg > octave-lyh > gnulib-hg
changeset 1999:5c262d8ca0d3
(jm_AC_FUNC_LINK_FOLLOWS_SYMLINK): New file/macro.
author | Jim Meyering <jim@meyering.net> |
---|---|
date | Sat, 06 Nov 1999 21:30:16 +0000 |
parents | d63c4f8e5a00 |
children | 64d5b25ae315 |
files | m4/link-follow.m4 |
diffstat | 1 files changed, 55 insertions(+), 0 deletions(-) [+] |
line wrap: on
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new file mode 100644 --- /dev/null +++ b/m4/link-follow.m4 @@ -0,0 +1,55 @@ +#serial 1 +dnl Run a program to determine whether whether link(2) follows symlinks. +dnl Set LINK_FOLLOWS_SYMLINKS accordingly. + +AC_DEFUN(jm_AC_FUNC_LINK_FOLLOWS_SYMLINK, +[dnl + AC_CACHE_CHECK([whether link(2) follows symlinks], + jm_ac_cv_func_link_follows_symlink, + [ + # Create a regular file, `conftest.file'. + echo > conftest.file + AC_TRY_RUN( + [ +# include <sys/types.h> +# include <sys/stat.h> +# ifdef HAVE_UNISTD_H +# include <unistd.h> +# endif + +# define SAME_INODE(Stat_buf_1, Stat_buf_2) \ + ((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \ + && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev) + + int + main () + { + const char *file = "conftest.file"; + const char *sym = "conftest.sym"; + const char *hard = "conftest.hard"; + struct stat sb_file, sb_hard; + + /* Create a symlink `conftest.sym' to it. */ + if (symlink (file, sym)) + abort (); + + /* Create a hard link `conftest.hard' to that symlink. */ + if (link (sym, hard)) + abort (); + + if (lstat (hard, &sb_hard)) + abort (); + if (lstat (file, &sb_file)) + abort (); + + /* If the dev/inode of hard and file are the same, then + the link call followed the symlink. */ + return SAME_INODE (sb_hard, sb_file) ? 0 : 1; + } + ], + jm_ac_cv_func_link_follows_symlink=yes, + jm_ac_cv_func_link_follows_symlink=no, + jm_ac_cv_func_link_follows_symlink=yes, We're cross compiling. + ) + ]) +])