c - How to print Bytes in order in a endian-portable way? -

c - How to print Bytes in order in a endian-portable way? -

i used simple function extensively in multi-threaded program:

char *serial2string(char *serial) { static char str[length * 2 + 1]; sprintf(str, "%08x%08x", ntohl(*(uint32_t *)(&serial[0])), ntohl(*(uint32_t *)(&serial[length / 2]))); homecoming str; }

i phone call different thread context, , static variable not protected against concurrency. bug happen sooner or later... created function simplify code needed, created concurrency issue. looking way either:

have function concurrent-safe. holding mutex work. create code uglier/heavier already. have macro or one-liner doing same thing simple plenty copy/paste everywhere need it. inlining works believe there better way.

in other words, how can print length bytes in order portable way (from endianness point of view) in thread-safe way?

edit phone call straight in printf statement:

printf("error: no such device, serial:%s\n", serial2string(&buf[1]));

i see couple of options.

allocate string within function malloc:

const char *str = serial2string(serial); // utilize string, free when you're done free(str);

alternatively, create caller pass in memory string:

char str[256]; str = serial2string(serial, str, 256);

if utilize exclusively within printf, following:

#define serial_format "%08x%08x" #define serial2str(s) ntohl(*(uint32_t *)(&s[0])), ntohl(*(uint32_t *)(&s[length / 2])) printf("the serial is:" serial_format "\n", serial2str(serial));

c linux endianness