modbus_set_debug - Man Page

set debug flag of the context


int modbus_set_debug(modbus_t *ctx, int flag);


The modbus_set_debug() function shall set the debug flag of the modbus_t context by using the argument flag. By default, the boolean flag is set to FALSE. When the flag value is set to TRUE, many verbose messages are displayed on stdout and stderr. For example, this flag is useful to display the bytes of the Modbus messages.

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Return Value

The function shall return 0 if successful. Otherwise it shall return -1 and set errno.


The libmodbus documentation was written by Stéphane Raimbault <>

Referenced By


01/25/2024 libmodbus v3.1.7 libmodbus Manual