_X_A_l_l_o_c_C_o_l_o_r can generate a _B_a_d_C_o_l_o_r error.
The _X_A_l_l_o_c_N_a_m_e_d_C_o_l_o_r function looks up the named color with respect to the screen that is associated with the specified colormap. It returns both the exact database definition and the closest color supported by the screen. The allocated color cell is read-only. The pixel value is returned in screen_def_return. If the color name is not in the Host Portable Character Encoding, the result is implementation-dependent. Use of uppercase or lowercase does not matter. If screen_def_return and exact_def_return point to the same structure, the pixel field will be set correctly, but the color values are undefined. _X_A_l_l_o_c_N_a_m_e_d_C_o_l_o_r returns nonzero if a cell is allocated; otherwise, it returns zero.
_X_A_l_l_o_c_N_a_m_e_d_C_o_l_o_r can generate a _B_a_d_C_o_l_o_r error.
delim %% The _X_A_l_l_o_c_C_o_l_o_r_C_e_l_l_s function allocates read/write color cells. The number of colors must be positive and the number of planes nonnegative, or a _B_a_d_V_a_l_u_e error results. If ncolors and nplanes are requested, then ncolors pixels and nplane plane masks are returned. No mask will have any bits set to 1 in common with any other mask or with any of the pixels. By ORing together each pixel with zero or more masks, ncolors * %2 sup nplanes% distinct pixels can be produced. All of these are allocated writable by the request. For _G_r_a_y_S_c_a_l_e or _P_s_e_u_d_o_C_o_l_o_r, each mask has exactly one bit set to 1. For _D_i_r_e_c_t_C_o_l_o_r, each has exactly three bits set to 1. If contig is _T_r_u_e and if all masks are ORed together, a single contiguous set of bits set to 1 will be formed for _G_r_a_y_S_c_a_l_e or _P_s_e_u_d_o_C_o_l_o_r and three contiguous sets of bits set to 1 (one within each pixel subfield) for _D_i_r_e_c_t_C_o_l_o_r. The RGB values of the allocated entries are undefined. _X_A_l_l_o_c_C_o_l_o_r_C_e_l_l_s returns nonzero if it succeeded or zero if it failed.
_X_A_l_l_o_c_C_o_l_o_r_C_e_l_l_s can generate _B_a_d_C_o_l_o_r and _B_a_d_V_a_l_u_e errors.
delim %% The specified ncolors must be positive; and nreds, ngreens, and nblues must be nonnegative, or a _B_a_d_V_a_l_u_e error results. If ncolors colors, nreds reds, ngreens greens, and nblues blues are requested, ncolors pixels are returned; and the masks have nreds, ngreens, and nblues bits set to 1, respectively. If contig is _T_r_u_e, each mask will have a contiguous set of bits set to 1. No mask will have any bits set to 1 in common with any other mask or with any of the pixels. For _D_i_r_e_c_t_C_o_l_o_r, each mask will lie within the corresponding pixel subfield. By ORing together subsets of masks with each pixel value, ncolors * %2 sup (nreds+ngreens+nblues)% distinct pixel values can be produced. All of these are allocated by the request. However, in the colormap, there are only ncolors * %2 sup nreds% independent red entries, ncolors * %2 sup ngreens% independent green entries, and ncolors * %2 sup nblues% independent blue entries. This is true even for _P_s_e_u_d_o_C_o_l_o_r. When the colormap entry of a pixel value is changed (using _X_S_t_o_r_e_C_o_l_o_r_s, _X_S_t_o_r_e_C_o_l_o_r, or _X_S_t_o_r_e_N_a_m_e_d_C_o_l_o_r), the pixel is decomposed according to the masks, and the corresponding independent entries are updated. _X_A_l_l_o_c_C_o_l_o_r_P_l_a_n_e_s returns nonzero if it succeeded or zero if it failed.
_X_A_l_l_o_c_C_o_l_o_r_P_l_a_n_e_s can generate _B_a_d_C_o_l_o_r and _B_a_d_V_a_l_u_e errors.
The _X_F_r_e_e_C_o_l_o_r_s function frees the cells represented by pixels whose values are in the pixels array. The planes argument should not have any bits set to 1 in common with any of the pixels. The set of all pixels is produced by ORing together subsets of the planes argument with the pixels. The request frees all of these pixels that were allocated by the client (using _X_A_l_l_o_c_C_o_l_o_r, _X_A_l_l_o_c_N_a_m_e_d_C_o_l_o_r, _X_A_l_l_o_c_C_o_l_o_r_C_e_l_l_s, and _X_A_l_l_o_c_C_o_l_o_r_P_l_a_n_e_s). Note that freeing an individual pixel obtained from _X_A_l_l_o_c_C_o_l_o_r_P_l_a_n_e_s may not actually allow it to be reused until all of its related pixels are also freed. Similarly, a read-only entry is not actually freed until it has been freed by all clients, and if a client allocates the same read-only entry multiple times, it must free the entry that many times before the entry is actually freed.
All specified pixels that are allocated by the client in the colormap are freed, even if one or more pixels produce an error. If a specified pixel is not a valid index into the colormap, a _B_a_d_V_a_l_u_e error results. If a specified pixel is not allocated by the client (that is, is unallocated or is only allocated by another client) or if the colormap was created with all entries writable (by passing _A_l_l_o_c_A_l_l to _X_C_r_e_a_t_e_C_o_l_o_r_m_a_p), a _B_a_d_A_c_c_e_s_s error results. If more than one pixel is in error, the one that gets reported is arbitrary.
_X_F_r_e_e_C_o_l_o_r_s can generate _B_a_d_A_c_c_e_s_s, _B_a_d_C_o_l_o_r, and _B_a_d_V_a_l_u_e errors.