XvQueryAdaptors(3)

💖 NAME 💖

XvQueryAdaptors — bestie, this is the one that pulls up all the adaptor info for a screen. like, the whole roster. 🎀

---

✨ SYNOPSIS ✨

#include <X11/extensions/Xvlib.h>

int XvQueryAdaptors(Display *dpy, Window window,
                    unsigned int *p_num_adaptors,
                    XvAdaptorInfo **pp_adaptor_info);

okay so this is from libXv, the manual page lives in section 3, and she's serving c function realness 💅

---

🌸 ARGUMENTS 🌸

• dpy — the connection to the X server. your whole vibe-link to the display, no cap.
• window — a window of the screen you want adaptor info for. literally any window on that screen, she'll figure out which screen you mean from it. 🪟
• p_num_adaptors — a pointer to where the number of adaptors for the specified screen gets dropped off. you give her the address, she fills it in. ✨
• pp_adaptor_info — a pointer to where the list of returned adaptor information lands. yes that's a pointer to a pointer. she's that kind of girl. 💅

---

👑 DESCRIPTION 👑

So XvQueryAdaptors(3) returns video adaptor information for the screen of the specified drawable. iconic behaviour honestly.

The XvAdaptorInfo structure has this exact organization:

typedef struct {
  XvPortID base_id;
  unsigned long num_ports;
  char type;
  char *name;
  unsigned long num_formats;
  XvFormat *formats;
  unsigned long num_adaptors;
} XvAdaptorInfo;

and here's what each lil field is giving:

• base_id — the resource ID of the first adaptor port. the origin point, the main character's entrance. ⭐
• num_ports — how many ports this adaptor supports.
• type — a bit mask, okay pay attention bestie 🫶. XvInputMask is asserted if the adaptor supports video input, and XvOutputMask is asserted if it supports video output. AND in Xv protocol 2.2 and later, there are 3 new bits defined — XvVideoMask, XvStillMask and XvImageMask — indicating the adaptor is capable of video, still or image primitives respectively. three new icons dropped in the update, we love to see it. 🔥
• name — a vendor specific name that identifies the adaptor. her government name, basically.
• num_formats — the number of depth/visual id formats supported by the adaptor.
• formats — a pointer to an array of XvFormat structures.

and the XvFormat structure looks like THIS:

typedef struct {
  char depth;
  unsigned long visual_id;
} XvFormat;

• depth — a drawable depth supported by the adaptor.
• visual_id — a visual-id supported for the given depth by the adaptor. the two of them are a package deal, fr fr. 🦋

---

🌈 RETURN VALUES 🌈

• [Success] — returned if XvQueryAdaptors(3) completed successfully. she ate and left no crumbs. 💅
• [XvBadExtension] — returned if the Xv extension is unavailable. the extension ghosted you, sorry babe 😭
• [XvBadAlloc] — returned if XvQueryAdaptors(3) failed to allocate memory to process the request. no room, no memory, no service. 💀

---

🩺 DIAGNOSTICS 🩺

• [Drawable] — returned if the requested drawable does not exist. you asked for a window that isn't there. she looked. she found nothing. 🙈

---

🔗 SEE ALSO 🔗

• XvFreeAdaptorInfo(3) — yes bestie, you HAVE to free that info afterwards. go read it, it's the sequel. ✨

---

reminder: this page is part of the libXv Functions crew, and she's the XvQueryAdaptors(3) one. 🎀

okay that's the whole thing, love u, go free your adaptor info 🫶

X Version 11 · libXv 1.0.13 · XvQueryAdaptors(3) — mwah, bye bestie! 💖✨🌸