function::sprint_ustack - Linux

Overview

The function::sprint_ustack tool is used for fetching a brief description of the arguments passed as function arguments in placeholders. It’s a glibc function that can be utilized to get a stack trace of the program.

Syntax

static const char * function::sprint_ustack(struct ustack * usp, int entries)

• usp: pointer to the ustack to be printed.
• entries: number of stack frames to print. If zero, print all entries.

Options/Flags

N/A

Examples

Displaying the stack trace

#include <execinfo.h>
#include <stdio.h>

int main(void) {
    void *trace[16];
    int trace_size = backtrace(trace, 16);
    char **messages = backtrace_symbols(trace, trace_size);
    for (int i = 0; i < trace_size; ++i) {
        printf("%s\n", messages[i]);
    }
    free(messages);
    return 0;
}

Generating a string with the stack trace

#include <execinfo.h>
#include <stdio.h>
#include <string.h>

int main(void) {
    void *trace[16];
    int trace_size = backtrace(trace, 16);
    char **messages = backtrace_symbols(trace, trace_size);
    char buffer[4096];
    size_t buffer_size = sizeof(buffer);
    char *start = buffer;
    for (int i = 0; i < trace_size; ++i) {
        size_t len = strlen(messages[i]);
        if (start + len + 1 >= buffer + buffer_size) {
            break;
        }
        strcpy(start, messages[i]);
        start += len + 1;
        *start = '\n';
        ++start;
    }
    *start = '\0';
    printf("%s\n", buffer);
    free(messages);
    return 0;
}

Common Issues

• Undefined behavior: Calling this function with an invalid value for entries may result in undefined behavior.

Integration

This command can be integrated with other Linux commands for advanced tasks. For example, it can be used with the gdb debugger to display the stack trace during debugging.

Related Commands

• backtrace: Print a stack trace of the current program.
• backtrace_symbols: Convert an array of stack frames into an array of strings.