diff options
Diffstat (limited to 'm4/getdtablesize.m4')
| -rw-r--r-- | m4/getdtablesize.m4 | 56 |
1 files changed, 35 insertions, 21 deletions
diff --git a/m4/getdtablesize.m4 b/m4/getdtablesize.m4 index 1af2a247..4cc1a8ff 100644 --- a/m4/getdtablesize.m4 +++ b/m4/getdtablesize.m4 @@ -1,5 +1,5 @@ -# getdtablesize.m4 serial 6 -dnl Copyright (C) 2008-2017 Free Software Foundation, Inc. +# getdtablesize.m4 serial 7 +dnl Copyright (C) 2008-2018 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. @@ -12,29 +12,43 @@ AC_DEFUN([gl_FUNC_GETDTABLESIZE], AC_CHECK_DECLS_ONCE([getdtablesize]) if test $ac_cv_func_getdtablesize = yes && test $ac_cv_have_decl_getdtablesize = yes; then - # Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft limit - # up to an unchangeable hard limit; all other platforms correctly - # require setrlimit before getdtablesize() can report a larger value. AC_CACHE_CHECK([whether getdtablesize works], [gl_cv_func_getdtablesize_works], - [AC_RUN_IFELSE([ - AC_LANG_PROGRAM([[#include <unistd.h>]], - [int size = getdtablesize(); - if (dup2 (0, getdtablesize()) != -1) - return 1; - if (size != getdtablesize()) - return 2; - ])], - [gl_cv_func_getdtablesize_works=yes], - [gl_cv_func_getdtablesize_works=no], - [case "$host_os" in - cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows - gl_cv_func_getdtablesize_works="guessing no" ;; - *) gl_cv_func_getdtablesize_works="guessing yes" ;; - esac]) + [dnl There are two concepts: the "maximum possible file descriptor value + 1" + dnl and the "maximum number of open file descriptors in a process". + dnl Per SUSv2 and POSIX, getdtablesize() should return the first one. + dnl On most platforms, the first and the second concept are the same. + dnl On OpenVMS, however, they are different and getdtablesize() returns + dnl the second one; thus the test below fails. But we don't care + dnl because there's no good way to write a replacement getdtablesize(). + case "$host_os" in + vms*) gl_cv_func_getdtablesize_works="no (limitation)" ;; + *) + dnl Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft + dnl limit up to an unchangeable hard limit; all other platforms + dnl correctly require setrlimit before getdtablesize() can report + dnl a larger value. + AC_RUN_IFELSE([ + AC_LANG_PROGRAM([[#include <unistd.h>]], + [int size = getdtablesize(); + if (dup2 (0, getdtablesize()) != -1) + return 1; + if (size != getdtablesize()) + return 2; + ])], + [gl_cv_func_getdtablesize_works=yes], + [gl_cv_func_getdtablesize_works=no], + [case "$host_os" in + cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows + gl_cv_func_getdtablesize_works="guessing no" ;; + *) gl_cv_func_getdtablesize_works="guessing yes" ;; + esac + ]) + ;; + esac ]) case "$gl_cv_func_getdtablesize_works" in - *yes) ;; + *yes | "no (limitation)") ;; *) REPLACE_GETDTABLESIZE=1 ;; esac else |