glibc has two versions of strerror_r, a standards compliant one and a GNU
specific one. The GNU one is chosen when _GNU_SOURCE is defined. g++ always
defines _GNU_SOURCE on linux platforms because glibc's headers won't compile
in C++ mode without it. The GNU strerror_r doesn't always modify the buffer
which causes empty error messages on linux.
This patch changes MakeErrMsg to use the return value of strerror_r to get
the string instead of assuming the buffer will be modified, on GLIBC.
Patch by Benjamin Kramer!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73396 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Unix/Unix.h b/lib/System/Unix/Unix.h
index 452226f..c2c06dd 100644
--- a/lib/System/Unix/Unix.h
+++ b/lib/System/Unix/Unix.h
@@ -79,12 +79,19 @@
return true;
char buffer[MAXPATHLEN];
buffer[0] = 0;
+ char* str = buffer;
if (errnum == -1)
errnum = errno;
#ifdef HAVE_STRERROR_R
// strerror_r is thread-safe.
if (errnum)
+# if defined(__GLIBC__) && defined(_GNU_SOURCE)
+ // glibc defines its own incompatible version of strerror_r
+ // which may not use the buffer supplied.
+ str = strerror_r(errnum,buffer,MAXPATHLEN-1);
+# else
strerror_r(errnum,buffer,MAXPATHLEN-1);
+# endif
#elif HAVE_STRERROR
// Copy the thread un-safe result of strerror into
// the buffer as fast as possible to minimize impact
@@ -97,7 +104,7 @@
// but, oh well, just use a generic message
sprintf(buffer, "Error #%d", errnum);
#endif
- *ErrMsg = prefix + ": " + buffer;
+ *ErrMsg = prefix + ": " + str;
return true;
}