diff options
| -rw-r--r-- | common/str.cpp | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/common/str.cpp b/common/str.cpp index 0d00cd9378..c51c544556 100644 --- a/common/str.cpp +++ b/common/str.cpp @@ -447,7 +447,21 @@ String String::printf(const char *fmt, ...) { int len = vsnprintf(output._str, _builtinCapacity, fmt, va); va_end(va); - if (len < (int)_builtinCapacity) { + if (len == -1) { + // MSVC doesn't return the size the full string would take up. + // Try increasing the size of the string until it fits. + + // We assume MSVC failed to output the correct, null-terminated string + // if the return value is either -1 or size. + int size = _builtinCapacity; + do { + size *= 2; + output.ensureCapacity(size-1, false); + va_start(va, fmt); + len = vsnprintf(output._str, size, fmt, va); + va_end(va); + } while (len == -1 || len >= size); + } else if (len < (int)_builtinCapacity) { // vsnprintf succeeded output._size = len; } else { |