Format specifiers for uint8_t, uint16_t, ...?

If I have an integer variable I can use sscanf as shown below by using the format specifier %d.

sscanf (line, "Value of integer: %d\n", &my_integer);

Where can I find format specifiers for uint8_t, uint16_t, uint32_t and uint64_t?

uint64_t has probably %lu.

Solution 1:

They are declared in <inttypes.h> as macros: SCNd8, SCNd16, SCNd32 and SCNd64. Example (for int32_t):

sscanf (line, "Value of integer: %" SCNd32 "\n", &my_integer);

Their format is PRI (for printf)/SCN (for scan) then o, u, x, X d, i for the corresponding specifier then nothing, LEAST, FAST, MAX then the size (obviously there is no size for MAX). Some other examples: PRIo8, PRIuMAX, SCNoFAST16.

Edit: BTW a related question asked why that method was used. You may find the answers interesting.

Solution 2:

As others said, include <stdint.h> header that defines the format macros. In C++, however, define __STDC_FORMAT_MACROS prior to including it. From stdint.h:

/* The ISO C99 standard specifies that these macros must only be
   defined if explicitly requested.  */
#if !defined __cplusplus || defined __STDC_FORMAT_MACROS