#include <openssl/err.h> unsigned long ERR_get_error(void); unsigned long ERR_peek_error(void); unsigned long ERR_peek_last_error(void); unsigned long ERR_get_error_line(const char **file, int *line); unsigned long ERR_peek_error_line(const char **file, int *line); unsigned long ERR_peek_last_error_line(const char **file, int *line); unsigned long ERR_get_error_line_data(const char **file, int *line, const char **data, int *flags); unsigned long ERR_peek_error_line_data(const char **file, int *line, const char **data, int *flags); unsigned long ERR_peek_last_error_line_data(const char **file, int *line, const char **data, int *flags);
ERR_peek_error() returns the earliest error code from the thread's error queue without modifying it.
ERR_peek_last_error() returns the latest error code from the thread's error queue without modifying it.
See ERR_GET_LIB(3) for obtaining information about location and reason of the error, and ERR_error_string(3) for human-readable error messages.
ERR_get_error_line(), ERR_peek_error_line() and ERR_peek_last_error_line() are the same as the above, but they additionally store the file name and line number where the error occurred in *file and *line, unless these are NULL.
ERR_get_error_line_data(), ERR_peek_error_line_data() and ERR_get_last_error_line_data() store additional data and flags associated with the error code in *data and *flags, unless these are NULL. *data contains a string if *flags&ERR_TXT_STRING. If it has been allocated by OPENSSL_malloc(), *flags&ERR_TXT_MALLOCED is true.