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189 } 190 191 div.refsect2 table { 192 margin-top: 0; 193 background-color: #e6e6e6; 194 width: 100%; 195 border: 0 solid #000; 196 padding: 2px; 197 font: normal 16px courier new, monospace !important; 198 } 199 200 div.refsect2 td { 201 background-color: #e6e6e6; 202 font: normal 16px courier new, monospace !important; 203 white-space:pre; 204 } 205 206 /* COPYRIGHT: This style formats the text of the copyright statement at the bottom of the page */ 207 div.refsect3 { 208 font: normal 11px verdana, sans-serif; 209 margin-top: 50px; 210 margin-bottom: 20px; 211 padding-top: 0; 212 padding-bottom: 0; 213 } 214 215</style> 216 <title>eglQueryContext</title> 217 <meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /> 218 </head> 219 <body> 220 <div class="refentry"> 221 <a id="eglQueryContext"></a> 222 <div class="titlepage"></div> 223 <div xmlns="" class="refnamediv"> 224 <h1>eglQueryContext</h1> 225 <p> 226 return <acronym xmlns="http://www.w3.org/1999/xhtml" class="acronym">EGL</acronym> rendering context information 227 </p> 228 </div> 229 <div class="refsynopsisdiv"> 230 <h2>C Specification</h2> 231 <div class="funcsynopsis"> 232 <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"> 233 <tr valign="bottom"> 234 <td> 235 <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">EGLBoolean <strong class="fsfunc">eglQueryContext</strong>(</code> 236 <td>EGLDisplay <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">display</var>, </td> 237 </td> 238 </tr> 239 <tr valign="top"> 240 <td> </td> 241 <td>EGLContext <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">context</var>, </td> 242 </tr> 243 <tr valign="top"> 244 <td> </td> 245 <td>EGLint <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">attribute</var>, </td> 246 </tr> 247 <tr valign="top"> 248 <td> </td> 249 <td>EGLint * <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">value</var><code>)</code></td> 250 </tr> 251 </table> 252 </div> 253 </div> 254 <div class="refsect1"> 255 <a id="parameters"></a> 256 <h2>Parameters</h2> 257 <div class="variablelist"> 258 <dl class="variablelist"> 259 <dt> 260 <span class="term"> 261 <em class="parameter"> 262 <code>display</code> 263 </em> 264 </span> 265 </dt> 266 <dd> 267 <p> 268 Specifies the EGL display connection. 269 </p> 270 </dd> 271 <dt> 272 <span class="term"> 273 <em class="parameter"> 274 <code>context</code> 275 </em> 276 </span> 277 </dt> 278 <dd> 279 <p> 280 Specifies the EGL rendering context to query. 281 </p> 282 </dd> 283 <dt> 284 <span class="term"> 285 <em class="parameter"> 286 <code>attribute</code> 287 </em> 288 </span> 289 </dt> 290 <dd> 291 <p> 292 Specifies the EGL rendering context attribute to be returned. 293 </p> 294 </dd> 295 <dt> 296 <span class="term"> 297 <em class="parameter"> 298 <code>value</code> 299 </em> 300 </span> 301 </dt> 302 <dd> 303 <p> 304 Returns the requested value. 305 </p> 306 </dd> 307 </dl> 308 </div> 309 </div> 310 <div class="refsect1"> 311 <a id="description"></a> 312 <h2>Description</h2> 313 <p> 314 <code class="function">eglQueryContext</code> returns in 315 <em class="parameter"><code>value</code></em> the value of 316 <em class="parameter"><code>attribute</code></em> for <em class="parameter"><code>context</code></em>. 317 <em class="parameter"><code>attribute</code></em> can be one of the following: 318 </p> 319 <div class="variablelist"> 320 <dl class="variablelist"> 321 <dt> 322 <span class="term"> 323 <code class="constant">EGL_CONFIG_ID</code> 324 </span> 325 </dt> 326 <dd> 327 <p> 328 Returns the ID of the EGL frame buffer configuration 329 with respect to which the context was created. 330 </p> 331 </dd> 332 <dt> 333 <span class="term"> 334 <code class="constant">EGL_CONTEXT_CLIENT_TYPE</code> 335 </span> 336 </dt> 337 <dd> 338 <p> 339 Returns the type of client API which the context 340 supports (one of 341 <code class="constant">EGL_OPENGL_API</code>, 342 <code class="constant">EGL_OPENGL_ES_API</code>, or 343 <code class="constant">EGL_OPENVG_API</code>). 344 </p> 345 </dd> 346 <dt> 347 <span class="term"> 348 <code class="constant">EGL_CONTEXT_CLIENT_VERSION</code> 349 </span> 350 </dt> 351 <dd> 352 <p> 353 Returns the version of the client API which the 354 context supports, as specified at context creation 355 time. The resulting value is only meaningful for an 356 OpenGL ES context. 357 </p> 358 </dd> 359 <dt> 360 <span class="term"> 361 <code class="constant">EGL_RENDER_BUFFER</code> 362 </span> 363 </dt> 364 <dd> 365 <p> 366 Returns the buffer which client API rendering 367 via the context will use. The value returned 368 depends on properties of both the context, and 369 the surface to which the context is bound: 370 </p> 371 <div class="itemizedlist"> 372 <ul class="itemizedlist" style="list-style-type: disc; "> 373 <li class="listitem"> 374 <p> 375 If the context is bound to a pixmap surface, 376 then <code class="constant">EGL_SINGLE_BUFFER</code> will 377 be returned. 378 </p> 379 </li> 380 <li class="listitem"> 381 <p> 382 If the context is bound to a pbuffer surface, 383 then <code class="constant">EGL_BACK_BUFFER</code> will 384 be returned. 385 </p> 386 </li> 387 <li class="listitem"> 388 <p> 389 If the context is bound to a window surface, 390 then either <code class="constant">EGL_BACK_BUFFER</code> 391 or <code class="constant">EGL_SINGLE_BUFFER</code> may be 392 returned. The value returned depends on both the 393 buffer requested by the setting of the 394 <code class="constant">EGL_RENDER_BUFFER</code> property 395 of the surface (which may be queried by calling 396 <code class="function">eglQuerySurface</code>), and on 397 the client API (not all client APIs support 398 single-buffer rendering to window surfaces). 399 </p> 400 </li> 401 <li class="listitem"> 402 <p> 403 If the context is not bound to a surface, such 404 as an OpenGL ES context bound to a framebuffer 405 object, then <code class="constant">EGL_NONE</code> will 406 be returned. 407 </p> 408 </li> 409 </ul> 410 </div> 411 </dd> 412 </dl> 413 </div> 414 </div> 415 <div class="refsect1"> 416 <a id="notes"></a> 417 <h2>Notes</h2> 418 <p> 419 Attributes <code class="constant">EGL_CONTEXT_CLIENT_TYPE</code> and 420 <code class="constant">EGL_RENDER_BUFFER</code> are supported only if 421 the EGL version is 1.2 or greater. 422 </p> 423 <p> 424 Attribute <code class="constant">EGL_CONTEXT_CLIENT_VERSION</code> is 425 supported only if the EGL version is 1.3 or greater. 426 </p> 427 </div> 428 <div class="refsect1"> 429 <a id="errors"></a> 430 <h2>Errors</h2> 431 <p> 432 <code class="constant">EGL_FALSE</code> is returned on failure, 433 <code class="constant">EGL_TRUE</code> otherwise. 434 <em class="parameter"><code>value</code></em> is not modified when 435 <code class="constant">EGL_FALSE</code> is returned. 436 </p> 437 <p> 438 <code class="constant">EGL_BAD_DISPLAY</code> is generated if 439 <em class="parameter"><code>display</code></em> is not an EGL display connection. 440 </p> 441 <p> 442 <code class="constant">EGL_NOT_INITIALIZED</code> is generated if 443 <em class="parameter"><code>display</code></em> has not been initialized. 444 </p> 445 <p> 446 <code class="constant">EGL_BAD_CONTEXT</code> is generated if 447 <em class="parameter"><code>context</code></em> is not an EGL rendering context. 448 </p> 449 <p> 450 <code class="constant">EGL_BAD_ATTRIBUTE</code> is generated if 451 <em class="parameter"><code>attribute</code></em> is not a valid context attribute. 452 </p> 453 </div> 454 <div class="refsect1"> 455 <a id="seealso"></a> 456 <h2>See Also</h2> 457 <p> 458 <a class="citerefentry" href="eglCreateContext.html"><span class="citerefentry"><span class="refentrytitle">eglCreateContext</span></span></a> 459 </p> 460 </div> 461 <div xmlns="" class="refsect3" lang="en" xml:lang="en"><a xmlns="http://www.w3.org/1999/xhtml" id="Copyright"></a><h4 xmlns="http://www.w3.org/1999/xhtml"></h4><img xmlns="http://www.w3.org/1999/xhtml" src="KhronosLogo.jpg" /><p xmlns="http://www.w3.org/1999/xhtml"></p> 462Copyright © 2003-2014 The Khronos Group Inc. 463Permission is hereby granted, free of charge, to any person obtaining a 464copy of this software and/or associated documentation files (the 465"Materials"), to deal in the Materials without restriction, including 466without limitation the rights to use, copy, modify, merge, publish, 467distribute, sublicense, and/or sell copies of the Materials, and to 468permit persons to whom the Materials are furnished to do so, subject to 469the condition that this copyright notice and permission notice shall be included 470in all copies or substantial portions of the Materials. 471</div> 472 </div> 473 </body> 474</html> 475
