Move (static) thread local last_error buffer into lsl_last_error function to avoid a MinGW bug

Author: tstenner

src/common.cpp

@@ -16,8 +16,6 @@
 #include <mmsystem.h>
 #endif
 
-thread_local char last_error[512] = {0};
-
 int64_t lsl::lsl_local_clock_ns() {
 	return std::chrono::nanoseconds(std::chrono::steady_clock::now().time_since_epoch()).count();
 }
@@ -43,7 +41,10 @@ LIBLSL_C_API void lsl_destroy_string(char *s) {
 	if (s) free(s);
 }
 
-LIBLSL_C_API const char *lsl_last_error(void) { return last_error; }
+LIBLSL_C_API const char *lsl_last_error(void) {
+	thread_local char last_error[LAST_ERROR_SIZE] = {0};
+	return last_error;
+}
 }
 
 // === implementation of misc functions ===

src/common.h

@@ -30,8 +30,6 @@ extern "C" {
 	"Please do not compile this with a lslboost version older than 1.45 because the library would otherwise not be protocol-compatible with builds using other versions."
 #endif
 
-extern thread_local char last_error[512];
-
 // the highest supported protocol version
 // * 100 is the original version, supported by library versions 1.00+
 // * 110 is an alternative protocol that improves throughput, supported by library versions 1.10+
@@ -40,6 +38,9 @@ const int LSL_PROTOCOL_VERSION = 110;
 // the library version
 const int LSL_LIBRARY_VERSION = 115;
 
+/// size of the lsl_last_error() buffer size
+const int LAST_ERROR_SIZE = 512;
+
 namespace lsl {
 /// A very large time duration (> 1 year) for timeout values.
 const double FOREVER = 32000000.0;

src/lsl_c_api_helpers.hpp

@@ -7,15 +7,15 @@
 /// Helper for LSL_STORE_EXCEPTION_IN
 #define LSLCATCHANDSTORE(ecvar, Exception, code)                                                   \
 	catch (Exception & e) {                                                                        \
-		strncpy(last_error, e.what(), sizeof(last_error) - 1);                                     \
+		strncpy(const_cast<char *>(lsl_last_error()), e.what(), LAST_ERROR_SIZE - 1);              \
 		int32_t *__ec = ecvar;                                                                     \
 		if (__ec != nullptr) *__ec = code;                                                         \
 	}
 
 /// Helper for LSL_STORE_EXCEPTION_IN
 #define LSLCATCHANDRETURN(Exception, code)                                                         \
 	catch (Exception & e) {                                                                        \
-		strncpy(last_error, e.what(), sizeof(last_error) - 1);                                     \
+		strncpy(const_cast<char *>(lsl_last_error()), e.what(), LAST_ERROR_SIZE - 1);              \
 		return code;                                                                               \
 	}