LIBUSB20(3)

💅 LIBUSB20(3) — Library Functions Manual 💅

ok so this is a page from the libusb20 manual (Library Functions Manual, bestie, that's the collection it lives in) and today's main character is libusb20_be_device_foreach, which is literally the function that lets you walk through every USB device plugged into your machine, one at a time. no cap. 🦋

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✨ NAME ✨

libusb20_be_device_foreach — iterate connected USB devices

like, a little tour of everything plugged in. so iconic of it. 🔥

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🌸 SYNOPSIS 🌸

library “libusb” #include <libusb20.h>

struct libusb20_device *
libusb20_be_device_foreach(struct libusb20_backend *pbe,
    struct libusb20_device *pdev);

ok so it takes a backend pointer and a device pointer, and it hands you back a device pointer. simple. clean. slay. ✨

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💖 DESCRIPTION 💖

The libusb20_be_device_foreach function iterates connected USB devices, one device at a time. yes bestie, one at a time, it's very polite about it. 🎀

the backend pointer pbe? you get that by calling libusb20_be_alloc_default(3). that's your starting ticket, go get it. 🎟️

the starting value of pdev is NULL. like, empty. nothing. a blank slate. 🫶

then you call libusb20_be_device_foreach again with pdev set to the return value of the previous call and boom, you get the next device. it remembers where you were. that's main character energy honestly. 👑

and like, once you actually want to do stuff with a USB device, you pass that pointer into a call to libusb20_dev_open(3). that's the moment it becomes real. 💅

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⭐ RETURN VALUES ⭐

• libusb20_be_device_foreach returns NULL for end of list. that's the "we're done here, the party's over" signal. 😭
• otherwise? it's a pointer to the next device. 🦋

so your loop condition lowkey writes itself. iykyk. 🌈

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🧚 EXAMPLES 🧚

ok this is the part you actually came for, fr fr:

#include <libusb20.h>
struct libusb20_backend *be = libusb20_be_alloc_default();
struct libusb20_device *device = NULL;
while ( (device = libusb20_be_device_foreach(be, device)) != NULL ) {
    if (libusb20_dev_open(device, 0) == LIBUSB20_SUCCESS) {
        /* do something */
        libusb20_dev_close(device);
    }
}
libusb20_be_free(be);

see how device starts as NULL and then feeds itself back in every round? that's the whole trick bestie, it's giving self-sustaining loop. obsessed. 💜

and notice the cleanup at the end — libusb20_be_free(be). free your backend, be a good citizen. 🫶✨

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🎀 SEE ALSO 🎀

• libusb20(3)
• libusb20_be_alloc_default(3)
• libusb20_be_free(3)
• libusb20_dev_open(3)

go read those too, they're all part of the same friend group. 🌸

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and that's the page!! 🎉 this one came from Debian, dated December 14, 2025, filed under LIBUSB20(3) — mwah, thanks for reading, ily, go enumerate some USB devices responsibly 💖🎀🦋