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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.
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As far as I understand printf() , it has to know the length of the supplied parameters to be able to parse the variable argument list. Since uint8_t and uint16_t use the same format specifier %u , how does printf() "know" how many bytes to process?
uint16_t is unsigned 16-bit integer. unsigned short int is unsigned short integer, but the size is implementation dependent. The standard only says it's at least 16-bit (i.e, minimum value of UINT_MAX is 65535 ).
In C, the unsigned 8-bit integer type is called uint8_t . It is defined in the header stdint. h . Its width is guaranteed to be exactly 8 bits; thus, its size is 1 byte.
printf("%u",x);
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.
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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 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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