From 39e9506a1e4419085ca3a71bd07d247c8b63f8c0 Mon Sep 17 00:00:00 2001 From: Howard Hinnant Date: Tue, 2 Apr 2013 15:46:31 +0000 Subject: [PATCH] Reference: http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20130325/077131.html llvm-svn: 178544 --- libcxx/src/support/win32/support.cpp | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/libcxx/src/support/win32/support.cpp b/libcxx/src/support/win32/support.cpp index 9e85077a7ada..2139a3f859e5 100644 --- a/libcxx/src/support/win32/support.cpp +++ b/libcxx/src/support/win32/support.cpp @@ -23,14 +23,23 @@ int asprintf(char **sptr, const char *__restrict fmt, ...) va_end(ap); return result; } + +// Like sprintf, but when return value >= 0 it returns a pointer to a malloc'd string in *sptr. +// If return >= 0, use free to delete *sptr. int vasprintf( char **sptr, const char *__restrict fmt, va_list ap ) { *sptr = NULL; - int count = vsnprintf( *sptr, 0, fmt, ap ); - if( (count >= 0) && ((*sptr = (char*)malloc(count+1)) != NULL) ) - { - vsprintf( *sptr, fmt, ap ); - sptr[count] = '\0'; + int count = vsnprintf( NULL, 0, fmt, ap ); // Query the buffer size required. + if( count >= 0 ) { + char* p = static_cast(malloc(count+1)); // Allocate memory for it and the terminator. + if ( p == NULL ) + return -1; + if ( vsnprintf( p, count+1, fmt, ap ) == count ) // We should have used exactly what was required. + *sptr = p; + else { // Otherwise something is wrong, likely a bug in vsnprintf. If so free the memory and report the error. + free(p); + return -1; + } } return count;