Hex Dump
The Hex Dump service provides a convenient interface for dumping untyped memory to a file or to standard output. It is useful in debugging problems that rely on low-level memory state. Hex Dump is given a pointer and a length to dump to the screen. Hex Dumps are printed in groups of 16 bytes in hexadecimal format.
The Hex Dump utility will suppress 0’s by displaying the first and last sixteen 0’s of a region of memory and suppressing also 0’s in between. This allows large regions of memory to be dumped without overwhelming the output. Suppressed 0’s are indicated by an ellipsis (i.e. …).
To the right of the hexadecimal interpretation of the bytes, the same 16 bytes are interpreted as ASCII characters as a convenience of the data contains ASCII data. Non-printable ASCII data is printed as a dot or period (i.e. a .).
Example
Hex Dump has an easy to use interface. You provide a pointer and a length to it to dump. You can also provide an indentation string.
hex_dump_to_fd(fd, "BITS",(void*)set->data,num_bytes,indent);
When invoked, The output looks something like that found in Listing 57. Note how lines with 0’s are suppressed. The fd is a file, which includes the possibility of using stdout or stderr. A title comes second followed by a pointer to the data and the number of bytes to dump. Finally, the indent is a null-terminated string to print before each line of the dump.
* BITS:
* 00007FCF60C97070 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
* 00007FCF60C97080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
* ...
* 00007FCF60CB7060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
API Services
-
void hex_dump(const char *title, const void *addr, const size_t len, const char *indent)
Prints the memory pointed to by addr for length len printing indent before each line. Dumping memory prints 16 bytes per line and suppresses all but the first and last 16 bytes of regions of all zeroes.
Returns
No return value.
Example Usage
hex_dump("BITS",(void*)set->data,num_bytes,indent);
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void hex_dump_to_fd(FILE *fd, const char *title, const void *addr, const size_t len, const char *indent)
Works the same as
hex_dump()but prints to the file fd instead.Returns
No return value.
Example Usage
FILE* fd = ?; hex_dump_to_fd(fd, "BITS",(void*)set->data,num_bytes,indent);